460 overheating help
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Cross-Country
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460 overheating help
I have a 460 in a 86 F250. I recently installed a new timing chain and high flow water pump. Before doing this it ran at about 195 - 200 degrees. The chain was very worn out. We got it back together and it is now running hot (230 degrees). We set the initial timing at 6 deg BTDC. We pulled the vac hose off the dist diaphram and capped it. We didn't look at the total timing. It has a 180 thermostat that we have checked and ruled out. Could it be that the timing is off and causing it to run hot? If so: what should it be set at? Thanks for any and all advice.
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Joined: Nov 2007
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From: Denver Metro Area, CO
The timing would need to be WAY off to affect the temperature to that degree, and there would be other signs telling you that something is wrong (wouldn't run well at all).
Given your description, I'd guess a water pump was installed with an impeller facing the "wrong" way as will happen when people install a pump intended for a Serpentine belt system onto an engine that uses V-belts.
They spin in opposite directions and the impellers accommodate that.
Guess it could be the thermostat is installed backwards, too, or maybe there's a lot of air in the system that needs to be burped out........
Given your description, I'd guess a water pump was installed with an impeller facing the "wrong" way as will happen when people install a pump intended for a Serpentine belt system onto an engine that uses V-belts.
They spin in opposite directions and the impellers accommodate that.
Guess it could be the thermostat is installed backwards, too, or maybe there's a lot of air in the system that needs to be burped out........
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
There is no reverse rotation on the 7.5 serpentine routing.
See Illustration 5-45.
http://www.daycoproducts.com/daycoweb.nsf/cf652a4feb630ad0862571a4005ae40c/1120b6e8f406fd3e862574c000569a91/$FILE/SerpentineBeltRoutingGuide.pdf
Another possibility is a radiator restriction causing the lower hose to collapse with the rpm's up.
Do you know if the lower hose has a support spring in it?
See Illustration 5-45.
http://www.daycoproducts.com/daycoweb.nsf/cf652a4feb630ad0862571a4005ae40c/1120b6e8f406fd3e862574c000569a91/$FILE/SerpentineBeltRoutingGuide.pdf
Another possibility is a radiator restriction causing the lower hose to collapse with the rpm's up.
Do you know if the lower hose has a support spring in it?
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
Try drilling a tiny hole in the thermostat flange to allow it to purge the air.
If you start it with the radiator cap off can you see the flow across the top of the core once it reaches 180*?
If you start it with the radiator cap off can you see the flow across the top of the core once it reaches 180*?
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pedant
Joined: Jan 2008
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From: EXTREME southwest CT
8-10* of advance is correct.
http://www.flickr.com/photos/24183730@N03/2340584319/http://www.flickr.com/photos/24183730@N03/2340584319/ by http://www.flickr.com/people/24183730@N03/, on Flickr
Are you sure your balancer hasn't slipped?
http://www.flickr.com/photos/24183730@N03/2340584319/http://www.flickr.com/photos/24183730@N03/2340584319/ by http://www.flickr.com/people/24183730@N03/, on Flickr
Are you sure your balancer hasn't slipped?
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From: Denver Metro Area, CO
The impeller pointing the wrong way is just a possibility I was bringing up.
Another possibility I thought of is the installation of a new fan with the blades pointing the wrong way.
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Joined: Feb 2010
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From: CASA GRANDE AZ
I have a 460 in a 86 F250. I recently installed a new timing chain and high flow water pump. Before doing this it ran at about 195 - 200 degrees. The chain was very worn out. We got it back together and it is now running hot (230 degrees). We set the initial timing at 6 deg BTDC. We pulled the vac hose off the dist diaphram and capped it. We didn't look at the total timing. It has a 180 thermostat that we have checked and ruled out. Could it be that the timing is off and causing it to run hot? If so: what should it be set at? Thanks for any and all advice.
did you use a adjustable timing chain ? and if so is it set straight up or advanced or retarded ?
pedant
Joined: Jan 2008
Posts: 23,576
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From: EXTREME southwest CT
I think all 460's got the three row radiator.
The timing is WAY off if it's set at 6 and the vacuum is disconnected.
With only centrifugal there's no way it could have enough advance at idle to burn the mixture correctly.
The timing is WAY off if it's set at 6 and the vacuum is disconnected.
With only centrifugal there's no way it could have enough advance at idle to burn the mixture correctly.
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Vaccum advance is your friend, at idle and for mileage, to be sure. You do plug it to set timing (8-10 degrees is normal) and then you hook up the vaccum again!
Straight centrifical would only work for a race tuned distributor with a fixed "point plate", and the curve set to add back in the advance the vaccum is no longer providing. All engines need a certain amount of initial, and a curve. CC
Straight centrifical would only work for a race tuned distributor with a fixed "point plate", and the curve set to add back in the advance the vaccum is no longer providing. All engines need a certain amount of initial, and a curve. CC
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Cross-Country
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Second time someonehas said that the dist might be off a tooth. It runs good and is set at 8 degrees BTDC. Could it be off a tooth and still have good performance and be able to set it at 8 - 10 degrees with a light?
pedant
Joined: Jan 2008
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From: EXTREME southwest CT
Sure, if you have enough room to swing the vacuum advance can around instead of having it pointing straight forward.
If the timing chain is off a tooth moving the distributor is not going to fix the cam timing.
If the timing chain is off a tooth moving the distributor is not going to fix the cam timing.
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